[R] julian() and numerical noise

Uwe Ligges ligges at statistik.tu-dortmund.de
Fri Mar 23 19:47:08 CET 2012


On 23.03.2012 15:45, Andreas Eckner wrote:
> Hi,
>
> does anybody know if the following behavior of julian() is intentional?
>
>  > julian(2, 1, 2012) - julian(2 - 1e-15, 1, 2012)
> [1] 1
>  > julian(2, 1, 2012) - julian(2, 1 - 1e-15, 2012)
> [1] 0
>  > julian(2, 1, 2012) - julian(2, 1, 2012 - 1e-15)
> [1] 0
>
> In other words, julian() is subject to numerical noise in the 'day'
> argument, but not in the 'month' and 'year' argument? Another example:
>
>  > julian(2 - 1e-15, 1, 2012) - julian(1 - 1e-15, 1, 2012)
> [1] 30


Which vbersion of R are you talking about?

I get:

 > julian(2, 1, 2012) - julian(2 - 1e-15, 1, 2012)
Error in UseMethod("julian") :
   no applicable method for 'julian' applied to an object of class 
"c('double', 'numeric')"


Uwe Ligges


> Thanks,
> Andreas
>
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